Rice bran is a nutrient-dense composition derived from the milling of rice. Rice bran is a rich source of protein, fat, carbohydrate and a number of micronutrients such as vitamins, minerals, anti-oxidants and phytosterols. To be useful as a food ingredient, rice bran must be stabilized. That is, the lipid hydrolyzing and oxidizing enzymes present in the bran must be inactivated in order to prevent interaction of those enzymes, lipase and peroxidase in particular, with the oil fraction. If these enzymes are not inactivated, hydrolytic and oxidative rancidity will proceed, causing the formation of objectionable odors and flavors commonly associated with rancidity. Once stabilized however, rice bran serves as a dietary nutrient useful in a variety of food and beverage formulations.
The nutritional value of Stabilized Rice Bran (SRB) has been well recognized. Use of SRB in treatment of a number of human ailments, such as diabetes, coronary diseases, arthritis, and cancer, have been described in the following U.S. patents and published patent applications including: U.S. Pat. No. 5,985,344, issued Nov. 16, 1999, entitled, “Process for Obtaining Micronutrient Enriched Rice Bran Oil;” U.S. Pat. No. 6,126,943, issued Oct. 3, 2000, and entitled, “Method for Treating Hypercholesterolemia, Hyperlipidemia, and Atherosclerosis,” U.S. Pat. No. 6,303,586 issued Oct. 16, 2001, and entitled “Supportive Therapy for Diabetes, Hyperglycemia and Hypoglycemia;” U.S. Pat. No. 6,350,473, issued Feb. 26, 2002 and entitled “Method for Treating Hypercholesterolemia, Hyperlipidemia, and Atherosclerosis;” U.S. Pat. No. 6,558,714, issued May 6, 2003, and entitled “Method for Treating Hypercholesterolemia, Hyperlipidemia, and Atherosclerosis;” U.S. Pat. No. 6,733,799 issued May 11, 2004, and entitled “Method for Treating Hypercholesterolemia, Hyperlipidemia, and Atherosclerosis;” and U.S. Pat. No. 6,902,739, issued Jun. 7, 2005, and entitled “Method for Treating Joint Inflammation, Pain, and Loss of Mobility,” and U.S. Patent Application Publication US 2008/0038385 entitled “Therapeutic uses of an anti-cancer composition derived from rice bran.” Additional utilizations of SRB have been described in U.S. Patent Application Publication US 2009/0285919 entitled “Rice Bran Extracts for Inflammation and Methods of Use Thereof;” U.S. Patent Application Publication US 2009/0220666 entitled “Utilization of Stabilized Bran in High Protein Products;” U.S. Patent Application Publication US 2009/0191308 entitled “Method of Preparing Emulsified Cereal Bran Derivatives;” and U.S. Patent Application Publication US 2009/0162514 entitled “Production of Pasta Using Rice Bran and Rice Flour.” Each and every one of the foregoing patents and published patent applications are hereby incorporated by reference in their entireties for all that they teach and describe.
The nutrients in SRB are preferably extracted into a concentrated isolate for use in commercial food and beverage formulations. However, existing processes for the production of SRB derivatives provide inefficient yields and limited nutritional profiles compared to the potential available in SRB. Specifically, the enzyme alpha-amylase has been used to treat an aqueous slurry of SRB to convert the starch component of the SRB into a dextrin slurry that can be isolated by centrifugation and subsequent drying. However, the resulting dextrin product typically represents only forty to fifty percent of the starting weight of the SRB, and unlike nutrient-rich SRB, the dextrin product has a limited nutritional profile and is low in protein and antioxidant rich fat content. Not only is protein and fat needed for basic nutrition, the fat content in SRB has special qualities that can be maximized to enhance the nutraceutical nutritional value of the dextrin isolate. Specifically, the fat/oil component of SRB is dense with numerous antioxidants that provide SRB with an extremely high nutraceutical nutritional capacity. In most instances the antioxidant capacity of SRB is several magnitudes higher than foods more commonly known to be high in antioxidants. For instance, Xianli Wu et al., in the Journal of Food Composition and Analysis 17 (2004) at pages 407-422 (incorporated herein by reference), listed total antioxidant capacity (hydrophilic and lipophylic ORACFL) of 28 selected foods. When compared to rice bran, with results expressed as μmol Trolox Equivalents (TE) per gram fresh weight (FW), the Lipophilic antioxidant capacity of rice bran measured 155, while the next highest food, avocado, measured less than 6. When more fully extracted scientific evidence suggests that such antioxidants can have numerous health benefits. For example, certain SRB derivatives have shown potential for lowering and stabilizing blood glucose in Type 2 diabetics, as described in Qureshi, A. A. et al, ‘Effects of stabilized rice bran, its soluble and fiber fractions, on blood glucose levels and serum lipid parameters in humans with diabetes mellitus Types I and II’, Journal of Nutritional Biochemistry, 2002, 13:175-187 (incorporated herein by reference). Thus, a need exists for an improved method of extracting enhanced nutritional potency from the SRB to increase the yield of the isolate and improve its nutraceutical nutritional profile, especially its yield of protein and antioxidant-rich fat.